1. Field of the Art
Embodiments of the present invention relate to electronic devices for viewing stereographic displays and, in particular, to actively shuttered three-dimensional (“3-D” or “3D”) glasses synchronized in time with 3D enabled televisions.
2. Description of the Related Art
Televisions (TVs), monitors, and other displays have evolved over the years from black and white images to color, analog signals to digital high definition television (HDTV) formats, and cathode ray tube (CRT) screens to plasma and liquid crystal display (LCD) technologies. Three-dimensional ready televisions may be the next major upgrade that the general public endorses by buying in large quantities.
Three-dimensional ready televisions commonly incorporate stereoscopic displays. Stereoscopic displays present a separate image to a viewer's left eye and a separate image to the viewer's right eye. Technologies to present separate images to a viewer's eyes include anaglyphs, which typically use red and blue lens glasses, polarized lens glasses, and active shutter lens glasses for actively blocking the viewer's eyes in rapid, period sequence. All such lenses for 3D glasses are typically non-corrective lenses in that they do not redirect the direction of light (e.g., by refraction) as it passes through the lens.
For many 3D-ready televisions coming to market, their manufactures have developed vendor-unique protocols for viewing based on active shutter techniques. With active shutter techniques, a 3D television rapidly (e.g., 30 frames per second or greater) and alternatingly shows separate images for a viewer's left and right eyes. A viewer typically wears glasses that have liquid crystal (LC) active shutters rapidly blocking the left and right eye views alternatively so that each eye sees the corresponding left and right images shown at the corresponding time on the display. This “active shutter” process preferably is periodically and/or continuously synchronized with synchronization signals transmitted from the TV.
Currently, using an infrared (IR) link for transmitting a synchronization signal from the television to the glasses has proven both technologically efficient and economically affordable. Hence, an IR link has become the de-facto consensus for many major TV brands.
Current IR links are comprised of at least two parts: (1) an IR transmitter, either built-in inside the TV front panel or external as peripheral; and (2) an IR receiver built-in on the frame of the 3D glasses. The 3D television's IR transmitter continuously sends a synchronization signal to the IR receiver on the 3D glasses. This synchronization signal aligns the 3D glasses' lens timing to that of the television and corrects for wander in the 3D glasses' clock circuitry.
There exists a need in the art for more efficient and less expensive 3D glasses technology for synchronization with 3D televisions.